Japanese Patent Application Publication No. 2017-55044 describes a semiconductor device. This semiconductor device includes a semiconductor element including a signal pad, an encapsulant encapsulating the semiconductor element, and a lead connected to the signal pad. The lead includes a first end located outside the encapsulant and a second end located within the encapsulant, and is connected to the signal pad via a bonding wire within the encapsulant. The lead includes an upper surface extending from the first end to the second end, and the upper surface includes a joined section where the bonding wire is joined and a rough section located within the encapsulant and having a higher surface roughness than the joined section. According to such a configuration, the rough section provided at the lead enhances adhesion between the lead and the encapsulant.